1. Field of the Invention
This invention relates generally to exercise machines, and is particularly concerned with an exercise machine with a pivoting user support which has a multiple cam linkage system.
2. Related Art
Movable user supports linked to the movement of an exercise arm are extremely common in exercise machines, and are generally known as composite motion exercise machines. U.S. Pat. No. 2,252,156 of Bell and U.S. Pat. No. 6,251,047 of Stearns show bicycle and exercise bike designs in which a seat or user support is linked to an exercise arm or crank and pedal system to provide up and down movement to the seat. The most common application of movable user supports is found in rowing and horse riding type exercise machines, which use the weight of the user as the exercise resistance. In U.S. Pat. No. 3,446,503 of Lawton, U.S. Pat. No. 4,743,010 of Geraci, and U.S. Pat. No. 5,342,269 of Huang, a seat and exercise arm are pivotally mounted on the base frame, with the seat linked to the exercise arm for dependent movement. U.S. Pat. No. 4,300,760 of Bobroff, U.S. Pat. No. 5,299,997 of Chen, U.S. Pat. No. 5,356,357 of Wang, U.S. Pat. No. 5,453,066 of Richter, U.S. Pat. No. 5,458,553 of Wu, U.S. Pat. No. 5,503,608 of Chang and U.S. Pat. No. 5,507,710 of Chen all show horse riding type exercise machines. They all consist of a user support pivotally attached to a base frame, and one or more exercise arms pivotally connected to the frame and pivotally linked to the user support.
U.S. Pat. No. 6,264,588 of Ellis shows a composite motion movement machine that has a moving exercise arm linked to a movable user support, and a pivoting truck system which is slidably connected to rails mounted both on the main frame and user support. The movable user support and exercise arm are both pivoted at the same point on the base frame, in front of the user support. A belt connects the exercise arm to the truck. When the exercise arm is pushed or pulled, the belt pulls the truck along the rails, forcing the user support to rotate about its pivotal connection to the frame. This design puts all of the user's weight on one side of the pivot, producing a high initial lifting resistance when the user starts the exercise, and also has no means for properly aligning the exercise arm and user support during the exercise movement.
Movable seats linked to exercise arms have also been used in multi-purpose exercise machines, such as U.S. Pat. No. 5,330,405 of Habing, U.S. Pat. No. 5,334,120 of Rasmussen, U.S. Pat. No. 5,669,865 of Gordon, U.S. Pat. No. 5,733,232 of Hsu, and U.S. Pat. No. 6,244,995 of Prsala. In U.S. Pat. No. 5,330,405 of Habing, a lever arm is pivotally connected to the base frame and supports a movable sub-frame including a user support which is also pivotally connected to the stationary base frame. An exercise arm is pivotally mounted on the sub-frame and linked to the lever arm via cables and pulleys, so that movement of the exercise arm pulls the cables lifting the lever arm, and causing the sub-frame to pivot about its connection to the base frame and rise against the weight of the user. U.S. Pat. No. 5,733,232 of Hsu shows another multi-purpose exercise machine with a pivoting seat, but in this case the back pad is stationary and only the seat pad is pivoted. Thus, the seat travels in an arcuate path without any secondary stabilization for the user, forcing the user to try to maintain their balance on the seat as it arcs upward. Also, in this design, the pivot point for the seat is located at a spacing behind the user position, so that all of the user's weight will oppose the user when starting an exercise from rest. Neither of these machines has any capability for aligning the user and user support with a rigid exercise arm, and thus do not maintain or support the user in the proper position throughout the exercise.
Gordon shows a multi-purpose exercise machine that has a hinged, two-piece user support that folds and unfolds with each exercise repetition. The user support consists of a seat portion and a backrest portion, which are pivotally connected together. The user support is pivotally connected to a main frame, as is a first exercise arm. This first exercise arm provides pressing and pulldown exercises. A second exercise arm is pivotally connected to the user support for providing leg exercises. This second arm travels with the seat portion of the user support. A connecting link pivotally connects the first exercise arm with the user support so that movement in the arm forces movement in the user support. The link connects to the user support at the same pivot that joins the seat portion with the backrest portion. In a second embodiment a flexible line connects the user support with the main frame and has user-engaging handles attached to one end so that movement to the handles results in movement to the user support. In this design, the flexible line acts as both connecting link and exercise arm. In both designs, the seat and backrest do not travel in a fixed relationship to each other and additional support such a footrest, safety belts and thigh gripping surfaces are required to keep the user properly and safely positioned in the user support. Because most of the combined weight of the user and user support remain on one side of the user support's gravitational centerline, this weight is used as partial exercise resistance. Movement of the user support is designed to be an exercise of its own, rather than providing proper positioning/alignment of the user relative to the exercise arm. The folding and unfolding of the two-piece user support constantly works the abdominal and low back muscles, which means that these muscles are being worked even when other exercises are being performed. The user cannot truly isolate any one specific muscle or muscle group. The stomach cannot be worked without working the low back, the arms, chest, shoulders, upper back and legs all must be worked with one another or at the least with both the stomach and low back. Because of this the user cannot fully fatigue other muscles as the abdominals and low back would fatigue first.
Current exercise machines with pivoting or movable user supports often do not accurately maintain proper positioning of the user throughout the exercise motion, can result in awkward hand or wrist positions, and often involve exaggerated and unnatural arcing movements, or linear, non-arcing arm movements, rather than the smaller elliptical movement associated with free weight or natural exercise movements. There is no provision for proper positioning of the user relative to the position of the user engaging portion of the exercise arm throughout the entire exercise motion. Often, an awkward starting or finishing position is required, potentially causing strain or injury.